/*
 * @(#)Args4jRegistry.java	1.0 Apr 17, 2008
 *
 *	The MIT License
 *
 *	Copyright (c) 2008 Malachi de AElfweald <malachid@gmail.com>
 *
 *	Permission is hereby granted, free of charge, to any person obtaining a copy
 *	of this software and associated documentation files (the "Software"), to deal
 *	in the Software without restriction, including without limitation the rights
 *	to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 *	copies of the Software, and to permit persons to whom the Software is
 *	furnished to do so, subject to the following conditions:
 *
 *	The above copyright notice and this permission notice shall be included in
 *	all copies or substantial portions of the Software.
 *
 *	THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 *	IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 *	FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 *	AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 *	LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 *	OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 *	THE SOFTWARE.
 */
package org.eoti.io.args4j;

import static org.eoti.util.log.LogUtil.log;

import java.util.ServiceLoader;
import java.util.concurrent.locks.ReentrantLock;

public class Args4jRegistry
{
	private static ReentrantLock singletonLock = new ReentrantLock();
	private static Args4jRegistry singleton;

	public static void install(){
		// If singleton != null, then just return (don't lock READ)
		if(singleton == null){
			// don't let more that one person create the singleton
			singletonLock.lock();

			// if we were waiting for a lock, then someone else already made it
			if(singleton == null)
				singleton = new Args4jRegistry();

			singletonLock.unlock();
		}
	}

	private Args4jRegistry()
	{
		ServiceLoader<Args4jService> loader = ServiceLoader.load(Args4jService.class);
		for(Args4jService service : loader)
			log(String.format("Args4jService loaded: %s will handle %s", service.getHandlerClass().getName(), service.getValueClass().getName()));
	}
}
